Silver nanoparticles have high activity and can be sintered even at low temperatures, and have therefore been specifically noted as a patterning material for poorly heat-resistant materials for quite some time. In particular, with the recent advancement in nanotechnologies, production of single-nano class particles has become possible relatively in a simplified manner.
Patent Reference 1 discloses a method of mass-producing silver nanoparticles, starting from silver oxide and using an amine compound. Patent Reference 2 discloses a method of producing silver nanoparticles, comprising mixing an amine and a starting material of silver compound, and melting them. Non-Patent Reference 1 describes production of a paste using silver nanoparticles. Patent Reference 4 discloses a technique of producing silver nanoparticles having extremely good dispersibility in liquid. On the other hand, Patent Reference 3 discloses a method of changing a protective material for metal nanoparticles, from A to B, which comprises adding a polar solvent where an organic protective material B having a functional group with a high affinity for metal particles, such as a mercapto group or the like is dissolved therein, to a non-polar solvent where metal nanoparticles protected with an organic protective material A exist, then stirring and mixing them.    Patent Reference 1: JP-A 2006-219693    Patent Reference 2: WO04/012884    Patent Reference 3: JP-A 2006-89786    Patent Reference 4: JP-A 2007-39718    Non-Patent Reference 1: Masami Nakamoto, et al., “Application of Silver Nanoparticles to Conductive Pastes”, Chemical Industry, by Kagaku Kogyo-Sha, October 2005, pp. 749-754